It is too early to reveal what offers will be put on the table, the ministers argued, particularly as the US has yet to make public its negotiating stance.

"It makes no sense to say now how much the EU is willing to transfer," German environment minister Sigmar Gabriel said at a press conference after the meeting.

"We were not quite able to reach consensus on the financing mechanism. This is an issue where the [European] Council will need more discussion time," said EU environment Commissioner Stavros Dimas, also in attendance at the ministers' meeting.

Recognising that northern industrialised nations are responsible for 75 percent of global warming, these countries have committed to making the bulk of CO2 reductions.

But because the EU also wants developing countries, particularly emerging nations such as China, India, Brazil, Mexico and Indonesia, to also commit to reductions, climate finance for the third world has become the main focus of discussion in the lead-up to the Copenhagen meeting.

The expected grand bargain in Denmark would be that if the EU and US stump up significant chunks of cash for cutting emissions and climate adaptation, developing countries will commit to considerable CO2 reductions in return.

Specifically, the EU is hoping for a commitment from the global south - with the exception of the least developed countries, mainly in sub-Saharan Africa - of CO2 reductions of between 15 and 30 percent on 1990 levels.

However, despite the speed with which the EU and US found €2.6 trillion to bail out financial institutions over the course of 2008, coming up with funds for third-world climate measures is now proving much more elusive.

At their Monday meeting, the environment ministers kicked the topic up to the level of EU heads of state, due to meet in Brussels on 19 and 20 March, meaning any decision must be taken unanimously. Prior to that, on 10 March, EU finance ministers are also to discuss the issue.

Environment ministers did however endorse the sum that the commission had suggested in its January proposals would need to be spent by all countries around the world to combat climate change - roughly €175 billion annually by 2020, with half of that having to be invested in the developing world.

Paris vs. Warsaw

The two issues of how much of that half would come from the EU and, crucially, how much from each EU member state are at the heart of debate between the ministers.

According to the commission's proposals, EU financing for the developing world would come either through an annual financial commitment on the basis of an agreed formula, or by a percentage of monies coming from revenues produced by the creation of a carbon market across all wealthy countries similar to Europe's Emissions Trading Scheme (ETS).

If the EU opts for the fixed commitments, the formula to share out the burden would involve a calculation based on a member state's GDP, its emissions in comparison to GDP, and the size of its population.

Paris wants added to this formula a consideration of the amount of emissions per capita.

France likes this idea because it has the lowest emissions per capita in the EU. Poland, meanwhile, is not such a great fan because of its dependence on coal, an extremely dirty source of energy.

Green groups and development agencies said they were getting impatient with the EU on the question of climate finance.

"While billions of taxpayers' money is being used to prop up failed banks and carmakers, not one eurocent is being pledged to help the developing world tackle a problem that Europeans helped create," said Joris den Blanken, a campaigner with Greenpeace, which is calling for annual contributions by the EU of around €35 billion for climate adaptation measures in the developing world.

Oxfam meanwhile said that delaying commitments for climate finance in poor countries puts any "global climate deal at risk".

"The EU needs to put money on the table now. Treating poor people's lives as a bargaining tool in climate negotiations is both immoral and misguided as a negotiating strategy," said Katia Maia, with Oxfam in Brazil.

30 percent not enough

The EU itself is committed to cutting its own carbon emissions by 20 percent by 2020 on 1990 levels, or 30 percent if other developed nations agree to a similar cut, although the UN's Intergovernmental Panel on Climate Change (IPCC) 2007 recommendations say wealthy nations must cut emissions by between 25 and 40 percent by 2020 if dangerous consequences for humanity and the environment are to be avoided.

Last month, Chris Field, a leading climate scientist with the IPCC, warned the 2007 predictions - upon which EU policy is based - are far too optimistic, meaning that CO2 reductions of 25-40 percent by 2020 are insufficient.

At the same time, many of those reductions committed to by the EU will not really be performed domestically, as a large chunk of the 20 or 30 percent will come from so-called carbon offsets - essentially where wealthy countries pay poorer ones to make their carbon cuts for them.